BAA traffic figures back Boris Johnson's estuary airport plans

BAA's January figures seem healthy enough, handling a record 5.2 million passengers – up 2.3% on the same period last year. But traffic to China fell by 0.7%, allowing enough of a gap for BAA to trot out the capacity argument

Foster and Partners artist impression of the Thames Hub, a four-runway Thames estuary airport. BAA's latest traffic figures back up the London mayor's argument for an airport. Photograph: Foster And Partners/PA

BAA drove another nail into the long-term prospects of the Kentish grey heron on Monday morning with the latest contribution to the national debate over airport capacity. Britain's largest airport group craves a third runway at Heathrow airport but that is highly unlikely, so every noise it makes on the need for more capacity plays into the hands of Boris Johnson's estuary airport campaign. The grey heron is the collateral damage here: it joins the avocet, little grebe and ringed plover among the birds that would be endangered by a four-runway behemoth appearing off the Isle of Sheppey.

BAA's January figures seem healthy enough, handling a record 5.2 million passengers – up 2.3% on the same period last year. But traffic to China fell by 0.7%, allowing enough of a gap for BAA to trot out the capacity argument. Colin Matthews, BAA's chief executive, said: "Heathrow's China traffic in January, including Hong Kong, was down by 0.7% versus the previous year. Through 2011 as a whole, Heathrow's China traffic was up 3% versus 2010." BAA could not confirm whether other airports suffered a similar dip in January traffic. Did Chinese new year play a role? Matthews added that continental rivals reported much stronger growth on their Chinese routes last year. "This growth rate was well short of the growth rates generated by other European hubs, with Paris and Frankfurt growing at 9% versus 2010 and Amsterdam growing at 6%."

Developing markets are a key factor in the capacity argument, with Matthews and Johnson united in arguing that lucrative destinations in China, India and Brazil are being cut off by the lack of runways in the south-east. However, it is Johnson who is likely to benefit most from BAA's statement.